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Publications and source records attributed to Zhao Zhigang.
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BACKGROUND: Prostate stem cell antigen (PSCA) is a recently identified glycosylphosphatidylinositol (GPI)-anchored cell surface protein belonging to the Thy-1/Ly-6 family of cell surface antigens. Prior data in prostate cancers indicated that PSCA is directly regulated by androgens and PSCA expression increases with high-tumor grade, advanced stage, extracapsular invasion, and androgen-independent progression. The effect of complete androgen ablation (CAA) on tumor PSCA mRNA expression has not been elucidated. The purpose of the present study was to investigate the variations in the expression levels of PSCA mRNA before and after CAA, and further evaluate the clinically prognostic value of PSCA in human prostate carcinoma. MATERIALS AND METHODS: PSCA in situ hybridization (ISH) was performed on the cancerous pretreatment biopsy or transurethral resection of prostate (TURP) tissue of 42 men with primarily organ-confined prostate cancer before CAA, and on their tumor tissue from radical retropubic prostatectomy after CAA with bicalutamide and goserelin acetate for 3 months prior to undergoing radical prostatectomy. Tumor cytoplasmic staining of PSCA mRNA was evaluated by two independent pathologists and the differences of PSCA mRNA expression levels between the samples before and after CAA were analyzed using the Student's t-test. Thirty-six to forty months follow-up studies after radical retropubic prostatectomy were performed and aimed at assessing the correlation of PSCA mRNA expression level with local recurrences or metastases from the cancer. RESULTS: The percent of cells positive for PSCA mRNA by ISH labeling declined from 67.3% (0-89%)+/-9.4% before CAA to 33.8% (0-92%)+/-7.7% after CAA (P<0.001). Before CAA, 40 of 42 cases (95.2%) were positive for PSCA mRNA labeling, however, after CAA the percentage of positive reactivity of PSCA mRNA was decreased to 27 of 40 cases (67.5%), in which none was found with local recurrences or distant metastases after radical prostatectomy on follow-up. This decline in PSCA mRNA labeling was dependent on the original tumor grade with Gleason score of or=8: 73.4%+/-13.8% (P<0.05, respectively). The rest 13 cases had the increased percentage of cells positive for PSCA mRNA after CAA, in which 3 cases were found with local recurrences and 4 cases with distant metastases from tumor on follow-up. CONCLUSIONS: Our data demonstrate that CAA for prostate cancer can suppress PSCA mRNA expression with a tumor grade dependence and the increased expression of PSCA mRNA after CAA may be a clinically adverse predictor for tumor recurrences or distant metastases.
BACKGROUND: Prostate stem cell antigen (PSCA) is a recently defined homologue of the Thy-1/Ly-6 family of glycosylphosphatidylinositol (GPI)-anchored cell surface antigens. The purpose of the present study was to examine the expression status of PSCA protein and mRNA in clinical specimens of human prostate cancer (Pca) and to validate it as a potential molecular target for diagnosis and treatment of Pca. MATERIALS AND METHODS: Immunohistochemical (IHC) and in situ hybridization (ISH) analyses of PSCA expression were simultaneously performed on paraffin-embedded sections from 20 benign prostatic hyperplasia (BPH), 20 prostatic intraepithelial neoplasm (PIN) and 48 prostate cancer (Pca) tissues, including 9 androgen-independent prostate cancers. The level of PSCA expression was semiquantitatively scored by assessing both the percentage and intensity of PSCA-positive staining cells in the specimens. Then compared PSCA expression between BPH, PIN and Pca tissues and analysed the correlations of PSCA expression level with pathological grade, clinical stage and progression to androgen-independence in Pca. RESULTS: In BPH and low grade PIN, PSCA protein and mRNA staining were weak or negative and less intense and uniform than that seen in HGPIN and Pca. There were moderate to strong PSCA protein and mRNA expression in 8 of 11 (72.7%) HGPIN and in 40 of 48 (83.4%) Pca specimens examined by IHC and ISH analyses, with statistical significance compared with BPH (20%) and low grade PIN (22.2%) samples (p < 0.05, respectively). The expression level of PSCA increased with high Gleason grade, advanced stage and progression to androgen-independence (p < 0.05, respectively). In addition, IHC and ISH staining showed a high degree of correlation between PSCA protein and mRNA overexpression. CONCLUSIONS: Our data demonstrate that PSCA as a new cell surface marker is overexpressed by a majority of human Pca. PSCA expression correlates positively with adverse tumor characteristics, such as increasing pathological grade (poor cell differentiation), worsening clinical stage and androgen-independence, and speculatively with prostate carcinogenesis. PSCA protein overexpression results from upregulated transcription of PSCA mRNA. PSCA may have prognostic utility and may be a promising molecular target for diagnosis and treatment of Pca.
OBJECTIVE: Prostate stem cell antigen (PSCA) is a recently defined homolog of the Thy-1/Ly-6 family of glycosylphosphatidylinositol (GPI)-anchored cell surface antigens. The objective of the present study was to examine the expression status of PSCA protein and mRNA in clinical specimens of human prostate cancer (PCa) and to validate it as a potential molecular target for diagnosis and treatment of PCa. METHODS: Immunohistochemical (IHC) and in situ hybridization (ISH) analyses of PSCA expression were simultaneously performed on paraffin-embedded sections of 20 benign prostatic hyperplasia (BPH), 20 prostatic intraepithelial neoplasm (PIN) and 48 prostate cancer (PCa) tissues, including 9 androgen-independent prostate cancers. The level of PSCA expression was semiquantitatively scored by assessing both the percentage and intensity of PSCA-positive staining cells in the specimens. We then compared the PSCA expression between BPH, PIN and PCa tissues and analyzed the correlations of PSCA expression level with pathological grade, clinical stage and progression to androgen-independence in PCa. RESULTS: In BPH and low grade PIN, PSCA protein and mRNA staining were weak or negative and less intense and uniform than that observed in high grade PIN (HGPIN) and PCa. Moderate to strong PSCA protein and mRNA expression were noted in 8 of 11 (72.7%) HGPIN and in 40 of 48 (83.4%) PCa specimens examined by IHC and ISH analyses, and their statistical significance was compared with BPH (20%) and low-grade PIN (22.2%) specimens (P < 0.05). The expression level of PSCA increased with a higher Gleason grade, advanced stage and progression to androgen-independence (P < 0.05). In addition, IHC and ISH staining revealed a high degree of correlation between PSCA protein and mRNA overexpression. CONCLUSIONS: Our data demonstrate that PSCA as a new cell surface marker is overexpressed in a majority of cases of human PCa. PSCA expression correlates positively with adverse tumor characteristics, such as increasing pathological grade (poor cell differentiation), worsening clinical stage and androgen-independence and speculatively with prostate carcinogenesis. PSCA may possess prognostic utility and may be a promising molecular target for diagnosis and treatment of PCa.